1. Field of the Invention
The present invention relates to a natural gas distribution system. More specifically, the present invention relates to a natural gas distribution system that includes a gas cylinder that includes a pair of collars disposed on each axial end of the gas cylinder, a delivery crate which has individual compartments for the storage of individual gas cylinders, a delivery truck which holds the crates and includes a ventilation system and a refueling truck which includes a ventilation system and a fuel pipeline system so that all of the empty cylinders disposed in the refueling truck can be simultaneously refilled.
2. Discussion of the Related Art
The utilization of natural gas as an alternative fuel source has become more popular in recent years. Accordingly, there has developed a need in the art to provide natural gas distribution system. For example, there is a need to provide a distribution system so that refilled natural gas cylinders can be delivered to the customer's site and empty gas cylinders can be removed from the customer's site. There is also a need in the art for a complete natural gas distribution system which includes modifying the gas cylinders so that they can be handled, stored and shipped without damaging the cylinder valve. Further, there is a need for a more efficient manner in which the gas cylinders can be stored, shipped and refilled.
Natural gas cylinders are generally safe. However, if the gas cylinder valve is damaged, the contents can rapidly vent, which can create an inflammable or explosive environment. In recognition of this danger, the Occupational Safety and Health Administration (OSHA) and the National Fire Protection Association (NFPA) have set up standards for compressed gas equipment which require that the cylinders be stored in well ventilated areas and protected from heat. Also, provisions must be made for protecting the valve from impacts, e.g., by stabilizing the cylinders against being tipped over. To accomplish this requirement, cylinders have been provided with protective collars. See for example U.S. Pat. No. 5,004,117 of Kitsuda. These prior art collars, however, tend to completely enclose the valve area and thus must be removed to permit ready access to the valve.
Since these cylinders must be moved about, it is also preferable to include a handle in the valve cover as shown in the Kitsuda patent. However, such handles at only one end of the cylinder make manipulation of the cylinder awkward.
Typically, gas cylinders are stored vertically in racks as shown, e.g., in U.S. Pat. Nos. 3,451,573 of Josephian; No. 3,602,368 of Gould; No. 3,993,344 of Bennett; Nos. 4,295,431 and 4,481,972 of Stavlo; and No. 4,605,126 of Goedken et al. This keeps the cylinders from tipping over, and thus helps to protect the valves. However, these racks do not provide very compact or accessible storage of the cylinders. As shown in these patents, the racks may be part of a gas delivery system where the racks are mounted in delivery trucks. Further, it is known in the art to refill the gas cylinders (when vertically mounted in the delivery truck as shown in U.S. Pat. No. 4,542,774 of Stavlo).
In addition to the valves of the cylinders, their bases are also vulnerable to physical damage. Also, it would be beneficial if the cylinders could be handled by both the valve and base ends. Further, more cylinders could be transported if the cylinders were positioned in a more compact manner than the vertical arrangement of the prior art, and if the cylinders could be refilled in this more compact arrangement. The present invention is directed to overcoming these and other problems with the prior art.